It is important for patients to remember that targeted therapy does not mean nontoxic therapy. Patients often associate chemotherapy with intravenous treatment, so when they are told that they can take a pill for their NSCLC, they tend to be very pleased. They may assume that a pill will not have any side effects or, if side effects do occur, that they will be negligible. However, all targeted agents have side effects because the pathways that we target in cancer cells are also found in normal cells. 

The initial precision therapies for NSCLC target either EGFR or ALK. Side effects of EGFR tyrosine kinase inhibitors (TKIs) such as gefitinib, erlotinib, afatinib, and osimertinib are an extension of the pharmacologic blockade of EGFR-regulated pathways and include skin changes and diarrhea, as well as the potential for other issues such as weakness, abnormal liver function tests, and pulmonary toxicity. ALK TKIs (eg, crizotinib, alectinib, ceritinib, and brigatinib) are also associated with a number of side effects that include edema and fatigue, as well as the potential for less common events such as pulmonary, gastrointestinal, neurologic, and cardiovascular issues. Multiple other TKIs directed against other molecular targets in NSCLC are now US Food and Drug Administration approved. These different TKIs have their own side-effect profiles, and some of them are quite unique.

Thus, all patients receiving targeted therapy should be carefully monitored and provided with counseling that is tailored to the particular agent that they are taking. While it is very important for both the patient and the oncologist to be familiar with the specific side effects of each agent, the challenge is that some of these molecular targets occur in only 1% or 2% of NSCLCs. Thus, oncologists who are treating multiple types of cancer may not see any patients in a given year with a specific abnormality. It can therefore be difficult for community oncologists to keep up with all of the potential toxicities associated with targeted treatments. Along with laboratory monitoring, it is helpful to have a pharmacist, nurse, or nurse pharmacist review the profile of the drug so that the patient can be counseled on what to look out for that may be specific to the TKI.